Photographic processes and compositions



Patented Nov. 28, 1944 Walter D. Baldsiefen, Metuchen, N. J., as'signor,

by mesne assignments, to E. I. (in Pontde Nemours 8: Company, Wilmington, Del., a corp'oration of Delaware No Drawing. Application June 13, 1941,

Serial No. 397,967

17 Claims. (01. 95-6) g This invention relates to photography. More particularly it relates to photographic processes for producing blue-black tones in silver images and to photographic elements and compositions therefor. In one of its important aspects, it relates to'radiation sensitive silver halide layers which contain novel compounds which impart blue-black tones to developed silver halide images. It also relates to photographic developer solutions and treating solutions which are useful for producing blue-black tones in developed silver images. a

An object of this invention was to find new and useful processes and agents for imparting blue-blacktones to developed photographic images. Afurther object is to provide new photographic' elements which can be processed in a simple manner to yield blue-black images. A further object is to modify fine grain silver halide emulsions so that they yield upon development blue-black images instead of neutral black or brown to sepia tones. A still further object is to modify fine-Brain silver halide emulsions suitablefor positive cinematographic prints which produce pleasing blue-black images without 10sing the fineness of grain during processing of photographic elements. Still another object is to provide simple and economical means for producing such biue-bla5k images.

invention.

It has been found that photographs in blueblacl: tones can be made by utilizing organic compounds containing at least one methylol or lower alkoxylmethyl radical attached to an amide nitrogen atom, or methylol nitromethanes in their production. The amide compounds include not only open chain amides but cyclic amides wherein no oxygen is present in the amide linkage.

The novel agents are brought into association with the silver salt layers at some sta e of the manufacture or processing of photographic ele ments. To be more specific, the novel agents may be added to silver halide emulsions or photographic elements such as plates, films and photographic papers containing such emulsion layers prior to or subsequent to-development of such materials or elements. The agents can be used in developing solutions or maybe included in the support for the photographic layer, subbing layers, any subor intermediate layer, backing layer or protective layer such as an anti-abrasion layer-or anti-static layer of such elements. In the case of photographic or printing papers. the

thereof.

for the paper, the paper pulp or in a coating on the paper support, included in the emulsions or protective layers therefor. In addition, it is possible to obtain satisfactory results by bathing films, plates or print papers in a solution of one of the novel agents prior to devel0pment or by add ing'the agentsto the developing baths employed in processing.

According to one important aspect of the in,- vention the agents are open. chain methylol amides and lower alkoxymethyl amides wherein the methylol or alkoxymethyl radical or radicals are attached directly to an amide nitrogen atom.

A preferred class of open chain methylolamides. includes the methylolureas wherein at least one methylol radical is attached to a nitrogen atom Symmetrical and unsymmetrical urea derivatives of this type are included. Preferred agents of this type have the general formula.-

Still other objects will be apparent from the herein described wherein at least one of the R's is a methylol radical (--CH2OH) and the other R's are the same or diflerent and may be hydrogen, hydrocarbon or methylol.

The degree of blue-black tone obtained with the novel agents of this invention varies with the halide ratio of the emulsion, the degree of hardness of the emulsion, the developer used and the particular agent chosen and other factors in a similar manner to known blue-black toning agents.

tographic emulsion processed. They are compatible with sensitizing dyes and other emulslon constituents as evidenced from the follow-. ingdescription.

The concentration of the particular compound used will vary according, to the manner in which it is applied to the photographic material; and as certain compounds are more potent than others, a certain amount of variation is to be expected when different compounds are employed in the same way. In general, molecular equivalents of different compounds wil1 approximate the desired effect and the optimum concentration of one substance can be translated into the correct concentration of another without agents may be included the barytes, the size harmful effects. The following table gives the The degree of tone also varies with the. particular type of sensitizing dye used in the pho- 2 approximate range of concentrations which will be found most suitable for the average blue-black agent in difierent applications:

Range of con- '1 ype of appllcation centmtion Per cent 1 In developers 0.05 to 0. 75 2 In emulsions 0.01 to 0.5 3 In anti-abrasion layer 0. 1 to 1.0 4 1n subbing layers. 0. 25 to 3.0 5 In film base 0. 5 to 3.5 6 In paper 0. 2 to 3. 7 In baths 0.05 to 1.0

In the practice of the invention, it has been determined that lesser quantities of the active ingredient are required in processes involving the addition of blue-black agents to the emulsion, if the film is aged for some time at elevated temperatures and humidity. The period of aging can vary from several months to a few hours depending upon the temperature to which the emulsion is subjected. Temperatures from 65 to 140 F. can be employed with proportionally shorter times of aging as the temperature is raised to the maximum. In applications 2 to 6 (vide supra) it is almost impossible to dispense with th aging period and obtain satisfactory results.

The invention will be further illustrated but is not intended to be limited by the following examples:

Example I Twenty milliliters of water in which is dissolved 0.1 gram of monomethylol urea were added to 1 liter of a fine grain photographic emulsion ready for pouring which contained 40 grams of a silver halide, comprising 95% silver bromide and silver iodide, and '70 grams of gelatin. The emul One and five-tenths grams of trimethylol melamine were dissolved in 150 ml. of water and added to 1 liter of a fine-grain photographic emulsion comprising 45 grams of mixed silver halides representing 98% silver bromide and 2% silver iodide and '7'? grams of gelatin. This emulsion was then coated on a suitable support and dried at a temperature of 110 F. for a period of 20 hours. At the end of this time the material was rehumidified at 80% humidity and exposed to an object field. After exposure, the element was processed in alkaline metol-hydroquinone developer and fixed in an acid-hardening fixing bath. A sharp blue-black image of high resolving powor was obtained instead of the neutral-black-tobrownish image of a control to which no blueblack agent had been added.

Example III I One thousand milliliters of a fine grain gelatinc-silver halide emulsion commonly used for lithographic practice and containing 60 grams of mixed silver halides per liter, comprising 97% .film was then rehumidified at 70 F. in an atmosphere of 75% humidity and exposed. After exposure in a camera, the film was developed in,

a standard metol hydroquinone solution-washed and fixed. It was found that the image had a distinctly blue-black tone as compared to that produced by control strips of the same film to which no blue-black agent had been added.

Example IV A photographic printing paper stock is coated with a chloro-bromide emulsion and bathed for a period of 5 minutes in a bath containing 2 grams of symmetrical dimethylol urea dissolved in 1 liter of Water. It is dried for some time and then printed. The exposed print is then developed in a metol-hydroquinone developer and fixed. The image obtained is a definite blue-black color in stead of the brownish-black obtained with an untreated control print.

Example V Example VI A photographic element bearing a. light-sensitive silver halide emulsion layer on a, suitable base is bathed for about an hour in a solution composed of 0.65 gram of symmetrical'dimethylol urea ina mixture of methyl alcohol and water.

\ The element is then dried at constant temperature and humidity and exposed in a known manner, developed and fixed. It is found that the image has a blue-black tone and that the tendency of the emulsion layer to soften during "processing is somewhat reduced.

Example VII usualmanner and it was found that an excellent blue-black image was obtained instead of the usual brown-black type.

Example VIII A solution containing 0.75 gram of trimethylol nitromethane dissolved in 20 ml. of water was added to a liter of a. gelatino-silver halide emulsion containing 50 grams of silver halide. The

" emulsion was then coated on a suitable base, dried and then held at" for 14 hours. At the end of this time the emulsion coating was exposed to light in the manner known to the-art, developed ly evident instead of the somewhat brownish tones obtained from a similar emulsion without the presence of the methylol compound.

' Example 1::

To 1 liter of the substratum solution used to anchor a silver halide emulsion to its support there is added 10 grams of trimethylol nitromethane. This solution-is then coated on a suitable film base and a fine grain silver-halide emulsion superimposed upon itas described in previous examples. After an agingperiod of about 1 week at slightly elevated temperature, the film is exposed and processed in the customary manner. A blue-black image is formed in the emulsion.

Example X One and five-tenths grams of tetrahydro-L3- dimethoxymethyl 5 beta hydroxyethyl s-triazone-2 oi the formula:

ornocm N-CH:

N-CHsCHsOH moon.

amide,dimethyloladipamide, methylol. acetamide, methylol phthalimide, N-methylol urethane, N- methylol-N-butyl urethane, dimethylolmelamine,

I N,N',N" -tris(methoxymethyl) melamine,

N,N',N"-tris(ethoxymethyl)melamine, N,N'-bis- (methoxymethyl) urea, tetrahydro 1,3-dimethoxymethyl-S-inethyl s triazone-2, N,N'-bis(methoxymethyl) uron, N,N' bis(methoxymethyl) oxamide, N,N' -bis(methoxymethyl)fumaramide,

N,N'-bis(methoxymethyl)succinamide, N,N'-bis- (methoxymethyl) sebacamide, N,N'-bis(methoxymethyl) adipamide, monomethylol and dimethylol nitromethane may also be used in like manner.

The novel agents of this invention as above stated may be utilized in the production of photographs in blue-black tones in many ways. They are com atible with the various components of were added to 1 liter of a photographic emulsion I containing approximately 50 grams of mixed silver halides representing 97% silver bromide and 3% silver iodide and containing 70 grams of gelatin. The emulsion was then coated on a suitable support and dried at a temperature of 120 C. for a period of 4 hours. The film was then rehumidified at 80 humidity and exposed. After development and fixation the film was washed and dried. When compared with a control of identical composition, but containing no triazone, which had been processed in the same way it was observed that the treated film had a distinctly blue-black tone.

Example XI One and three-tenths grams of N,N'-bis(meth-' oxymethyl) urea were dissolved in a small quantity of a suitable solvent and incorporated in 1000 ml. of a gelatino silver'bromo-iodide emulsion suitable for radiographic film and containing 8% combined sliver halides of which 2% were types of solutions and emulsions as previously a stated they are preferably used in emulsion my ers. In developing baths the eifect produced varies somewhat with the pH and composition of the particular solution used.

In place of the specific blueblack toning agents mentioned in the above examples may be substituted one or more other compounds having the aoove described characteristics in. like manner.

Likewise, the compounds of the several examples can be interchanged in any desired manner. Suitable additional compounds which are methylol amides or lower alkoxymethylamldes wherein the alkoxy radicals contains 1 to 5 carbon atoms include N,N' dimethyl monomethylol urea, cyclic dimethylol diurea (Goldschmidts compo nd), methylol formamide, dimethylc formdeveloping agents whichmakes them of consid-, 'erable value. They are particularly useful in providing fine grain emulsions for positive cinematographic pictures and yield excellent blue-black images on exposure and processing in the usual manners. I They are not limited as has been clearly dem onstrated above to any one special type of silver halide emulsion. On the contrary they may be used with various reducible silver salts, e. g. silver chloride, silver bromide and silver iodide, or various mixtures of any of these with one or more of the others. They are useful with cinema, lithographic, radiographic and camera film, stripping films, printing papers and the like hearing such emulsions. j 4

While the novel blue-black toning agents have been described as being useful with gelatinosilver halide'emulsion layers, they may be used with silver halide layers having various colloid binding agents or gelatin substitutes such as cellulose derivatives, regenerated cellulose, synthetic resins, agar-agar, albumins, gums, etc.

The agents have considerableutility and may beused'with'or in photographic emulsions containing sensitizing dyes such as cyanine, carbocyanine, pseudocyanine, kryptocyanine, neocyanine, merocyanine. styryl, cyazine, rhodanine and other dyes including the salts and bases. They may also be used with photographic desensitizing agents, fog inhibitingcompounds, emulsion stabilizers andhardeners etc. They may also be used with the usual types of surface active agents, spreading agents etc., such as the sodium higher alky sulfonates and sulfates, saponine, etc. n

One of the most important advantages of the invention is that it produces images on positive motion-picture film and on positive print papers with a distinctly blue-black tone that is pIeasing to the eye and creates the illusion of greater I materials employed do not hinder the normal processing of the film or paper and do not tend to increase defects in the emulsion such as fog to any measurable extent. An additional and equally major advantage is that they harden the emulsion.

Asmany apparently widely different embodideparting" from the spirit and scope thereof, it isto be understood that the invention is not to be limited to the speciilc embodiments herein except as defined by the appended claims.

I claim: Y

1. The process which comprises developing a photographic element containing a. reducible silver salt image in the presence of an organic amide having'at least one radical taken from the group consisting o! methylol and lower alkoxy-' methyl radicals directly attached to an amide nitrogen atom. 1

2. The process which comprises developing a photographic element containing a reducible silver salt image in the presence of \a. methylolamide wherein the methylol radical is attached to an amide nitrogen atom.

3. The process which comprises developing a photographicelement-ccntalning a reducible silver salt image in the presence of a methylolurea having at least one CH:OH group attached to an amide nitrogen atom thereof.

4. A photographic element comprising a support, a light sensitive silver salt layer and a stratum containing a small amount oi an organic amide havingat least oneradical taken from the group consisting of methylol and lower a1k'oxyport having a light sensitive silver halide emulsicn layer thereon, said layer containing one methylolurea having at leastone --CHsOH-- radical directly attachedto an amide nitrogen atom thereof.

10. A photographic element comprising a support having a light sensitive silver halide emulmethyl radicals directly attached to an amide nitrogen atom,

5; A photographic element comprising asupport, a light sensitive silver halide layer having intimately associated therewith at least one methylolamide having at least one --CH:OH radical directly attached to an amide nitrogen atom. 6. A phctogra'phic'element comprising asup port, a light sensitive silver halide layer having intimately associated therewith atleast one methylolurea having at least one CHsOI-I radical directly attached to an amide nitrogen atom.

thereof.

I. A photographic element comprising support having a light sensitive silver halide emulsion layer thereon and a stratum in intimate contact therewith containing a small amount of an organic amide having at least one, radical taken from the group consisting of methylol and lower alkoxymethyl radicals directly attached to an amide nitrogen atom.

11. A light sensitive silver halide emulsion containing a small amount of an organic amide having at least one radical takenfrom the group consisting of methylol and lower allto'm methyl oped photographic images in blue-black tones.

the step which comprises adding to a constituent of the emulsion layer prior to complete development a small amountoi arr-organic amide havinl at least one radical taken irom the group consisting oi methylol and lower alkoxymethyl radicals directly attached to. an amide nitrogen atom thereof v 14. An aged, light sensitive, silver halide. emulsion containin a small amount oi an organic amide having at least o e radical taken from the group consisting of me hylol and lower alkoxymethyl radiealsdirectly attached to an amide nitrogenatom thereof.

sion layer thereon said layer containing a small amount oi an organic amide having at least one nathylol radical attached to an amide nitrogen a, m.

I. A photographic element comprising a sup-' port having a light sensitive silver halide emulsion layer thereon, said a layer containing a small amount oi an organic amide taken from the class consisting of methylolamides and lower alhlethcrs thereoi wherein at least one --CH:O

i6..A photographicelement comprising a support having alight sensitive silver halide emulsion layer thereon. said layer containing a smell amolmt oi dimethylol urea.

16. A photographic element comprising a sur port having a light sensitive silver halide emul sion layer thereon, said layer containing a amount oi trimethylol melamine.

17. A photographic element comprising a sup- 90ft having a lilht sensitive silver halide emulfslcnlayer thereon. said layer containing a radical is directlyattached toan amidenitromatom.

0. A photographic element comprising a sun 5 amount of N,N'-his(methoxymethyl') urea.. 

